Antioxidative activities of hydrolysates from seabass skin prepared using protease from hepatopancreas of Pacific white shrimp Theeraphol Senphan, Soottawat Benjakul * Department of Food Technology, Faculty of Agro-Industry, Prince of Songkla University, Hat Yai, Songkhla 90112, Thailand ARTICLE INFO Article history: Received 7 August 2013 Received in revised form 2 October 2013 Accepted 3 October 2013 Available online 26 October 2013 Keywords: Fish skins Pacific white shrimp Seabass Alcalase Antioxidant activity ABSTRACT Antioxidative activities of hydrolysates from skin of seabass (Lates calcarifer) with different degrees of hydrolysis (DH: 10–40%) prepared using an ammonium sulphate precipitated fraction (ASPF) from Pacific white shrimp hepatopancreas and commercial Alcalase were compared. The hydrolysate prepared using ASPF or Alcalase had increases in 2,2-diphe- nyl-1-picrylhydrazyl (DPPH), 2,2-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging activities and ferric reducing antioxidative power (FRAP) as DH increased (P < 0.05). When the hydrolysate prepared using ASPF with 40% DH was subjected to a gastrointestinal model system (GIMs), ABTS radical scavenging activity and chelating activity increased, especially in the duodenal condition. The hydrolysate (500–2000 mg/L) could inhibit lipid oxidation in a lecithin liposome system in a dose dependent manner. Based on gel filtration using a Sephadexä G-15 column, peptide with a molecular weight of 364 Da showed the strongest ABTS radical scavenging activity. Therefore, the extract from hepatopancreas could be used to increase DH of hydrolysate from seabass skin. Ó 2013 Elsevier Ltd. All rights reserved. 1. Introduction Pacific white shrimp and its products have become econom- ically important for Thailand. By the year 2010, the total amount of frozen Pacific white shrimp and products was 408,000 metric tonnes and the products were mainly exported to the USA and Japan (Senphan & Benjakul, 2012). During shrimp processing, a large amount of by-products including cephalothorax, shell, etc. are generated (Senphan & Benjakul, 2012). Amongst all shrimp products, whole shrimp without hepatopancreas are currently showing increased demand. The hepatopancreas is removed using a vacuum sucking machine (Senphan & Benjakul, 2012). Shrimp hepatopancreas can be a major source of proteases, especially trypsin and chymotrypsin (Sriket et al., 2012). Proteases in the hepatopancreas from freshwater prawn actively hydrolysed various proteinaceous substrates (Sriket et al., 2012). Seabass (Lates calcarifer) are very popular in South-East Asia owing to their white flesh and delicacy (Sinthusamran, Benjakul, & Kishimura, 2013). During fillet production, skin is generated and can serve as a potential source for gelatin (Sinthusamran et al., 2013). Additionally, gelatin from fish skin has been used for production of gelatin hydrolysate with bioactivities (Ngo, Qian, Ryu, Park, & Kim, 2010). The benefi- cial effects of bioactive peptides are well known in scavenging free radicals and reactive oxygen species or in preventing the oxidative damage by interrupting the radical chain reaction of lipid peroxidation (Harnedy & FitzGerald, 2012; Kim & Wijese- kara, 2010). Gelatin hydrolysate from bigeye snapper skin, possessing antioxidative activity including DPPH and ABTS radicals scavenging activity and ferric reducing antioxidant 1756-4646/$ - see front matter Ó 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.jff.2013.10.001 * Corresponding author. Tel.: +66 7428 6334; fax: +66 7455 8866. E-mail address: soottawat.b@psu.ac.th (S. Benjakul). JOURNAL OF FUNCTIONAL FOODS 6 (2014) 147 – 156 Available at www.sciencedirect.com ScienceDirect journal homepage: www.elsevier.com/locate/jff